Ganoderma tsugae

Scientific name:   Ganoderma tsugae Murr.
Derivation of name:   Ganoderma means having a "shiny
or lustrous skin"; tsugae means hemlock (Tsuga), one of
its common hosts.
Synonymy:   Polyporus tsugae (Murr.) Overh.
Common names:   Hemlock varnish shelf.
Phylum:   Basidiomycota
Order:   Polyporales
Family:   Ganodermataceae
Occurrence on wood substrate: Saprobic; solitary or in
overlapping clusters on living and dead conifer trunks and
on stumps and logs; May through November, but these
annuals may overwinter.  
Dimensions:  Caps 5-30 cm; stipes (if present) 2.5-15 cm
long and 1-4 cm thick.   
Upper surface:  Shiny reddish to brownish-orange varnish;
white margin; concentrially furrowed; surface becomes dull
when coated by deposited spores.
Pore surface: Whitish, becoming brown in age or when
bruised; pores 4-6 per mm.
Edibility: Although inedible as is, a tea with medicinal
properties can be prepared from this shelf fungus.
Comments:  As the specific epithet suggests, a common
host for this species is hemlock (Tsuga canadensis).

More information at MushroomExpert.com:  

  
Figure 1. A beautiful fruiting of Ganoderma tsugae on a
stump. Photo © David Work.

Figure 2. Note the shiny, varnished surfaces of these young
specimens and the white margins. Photo © David Work

Figure 3. Very young specimens. Photo © David Work.

Figure 4. Note the clump of Hemlock varnish shelf
at the base of this hemlock tree.

Figure 5. The same tree as in Figure 4 only about 15 years
later. Whether as parasites or saprophytes, fungi are integrally
involved with the recycling of wood.

Figure 6. Although Ganoderma tsugae may appear terrestrial,
it is attached to wood, in this case buried wood.

Figure 7. Millions of spores are released from the undersides
of bracket fungi such as Ganoderma tsugae. Air currents
near the bracket cause some of these spores to land on the
top surface, dulling the shiny varnish layer.